Hair shampoos are a common household commodity in many communities around the world. The properties of a good shampoo often depend upon the intended application, but may include the ability to cleanse the hair and scalp of the user thoroughly, but without stinging, irritation or the removal of excess natural oils from the scalp, cosmetic and aesthetic characteristics including the imparting of lustre, softness and manageability and the formation of foam necessary for removal of dirt particles. Consumers consider foaming ability an important aesthetic consideration in assessing the acceptability of a shampoo.
Shampoos may be variously formulated as liquids, creams, pastes, aerosols or dry formulations. The majority are liquids, either clear or pearlised. The principal constituents of most liquid shampoos can be classified as detergents, thickeners, foam stabilisers and boosters, perfumes, preservatives, diluents or bulking agents (usually water), conditioning agents or emollients, pearlisers/opacifiers and colours. The bulking agents are included primarily for commercial purposes, so as to allow a consumer to dispense a typical amount of shampoo so as to achieve a desirable level of lather and cleaning.
In addition, some shampoos having a specialised application, such as minimisation of eye sting, treatment of dandruff or other scalp conditions, or which are formulated for specific hair types such as dry, oily, coloured or permed hair often contain further additives to fulfil their advertised purpose. It is desirable to combine the cleansing characteristics of a shampoo with medicated treatments for hair borne or skin-based diseases at least for convenience, if not for ease of application.
Shampoos in liquid form usually contain a large proportion of water. Water is frequently used as the bulking agent in liquid shampoos, because of its inert properties, its miscibility with other shampoo constituents, its low cost, and its ease of removal from hair during the normal washing process.
However, in instances where it is desirable to include an additive in a liquid shampoo, and in which the additive is not compatible with water, such as some medicaments, there is a need to find an alternative to the use of water as a bulking agent.
There are many difficulties in formulating a non-aqueous shampoo. For example, the use of alcohols in shampoos may reduce or destroy desirable foam formation. Alternatively, oils are often too greasy and so are cosmetically unacceptable in the amounts required. Exotic non-aqueous bulking agents are commercially prohibitive because of their high cost.
Various medicated compositions exist which are directed to the treatment of scalp or skin diseases, or to lice infestation in hair for example. U.S. Pat. No. 5,993,787 (JOHNSON & JOHNSON CONSUMER PRODUCTS INC) is directed to a topical preparation for treatment of fungal infections. This formulation is presented in the form of a lotion and has no cleansing characteristics such as are desirable in a medicated shampoo. Similarly, EP0028525 (ORION-YHTYMA OY) is directed to a topical solution applied to the scalp for treatment of alopecia, and AU599086 is directed to a topical treatment of scalp diseases but not in a shampoo format.
Other patented formulations are aqueous and so are not well suited to the incorporation of active agents which are insoluble in water. Amongst this class of prior art disclosures are U.S. Pat. No. 5,866,152 (SUMITOMO CHEMICAL COMPANY) directed to shampoos for treatment of lice, and U.S. Pat. No. 5,559,092 (CHEESEBOROUGH-PONDS USA CO.DIVISION OF CONOPCO, INC).
It is an object of the present invention to produce a non-aqueous liquid shampoo which contains an active agent such as for treatment of scalp or skin diseases, or for treatment of hair infestations in a composition which imparts desirable aesthetic characteristics to the hair being treated, has a satisfactory cleansing and foaming capacity, and which does not have undesirable effects on the user.